Typical slot car racing games use miniature model cars driven by an electric motor and gears inside them to rotate the drive wheels and tires. Electrical power is provided to the motor via brushes, sometimes called pick-up shoes, attached to the bottoms of the racecars that must drag on electrically energized conductive strips, sometimes called metal track rails, attached to the racetrack and connected to the controller/power supply. All of the components in the racecar wear amazingly fast and must be replaced often. In addition, the required number of components limits the miniaturization of the racecar and therefore the track. Another persistent problem is the accumulation of dirt, oxidation, and debris on the conductive strips of the track and on the racecar brushes, which interrupt the power supplied to the motor. This causes the racecar to move erratically or even stall. Cleaning these items can be a tedious and time-consuming operation to someone (especially a child) that just wants to play a game.
One system has been proposed to overcome some of these problems, but with extreme trade-offs. It uses a non-powered racecar that receives a “kick” from one or more spinning wheels affixed to a single location on the track powered by an electric motor. The wheel(s) spin at a high rpm and accelerate any car that engages the wheel(s). The car then coasts around the track until it reaches the spinning wheel(s) again. The operator may control the rpm of the spinning wheel(s) but has no control of the racecar speed except at the one point in the track where the car engages the spinning wheel(s).
Linear motors are used for industrial systems and magnetic levitation (maglev) trains. These devices are complex and far too expensive for use in toy systems. The linear motors contain coils of copper wire with ferrous cores distributed along the track, or even permanent magnets distributed along the track, or the moveable object itself has coils that must be electrically powered. Also the position of the moveable object must be continuously sensed with sophisticated instrumentation and fed back to the controller for proper operation.